Propellant powder and process of making same



Patented STATES PATENT ori ice.

ARTHUR S. ONEIL, OF ALTON, ILLINOIS, ASSIGNOR T WESTERN CARTRIDGE COMPANY, OF EAST ALTON, ILLINOIS, A CORPORATION OF DELAWARE.

PROPELLANT POWDER AND rao cnss or MAKING SAME.

No Drawing.

This invention relates to propellant powders, and more particularly to nitro-cellulose powders adapted for'use in and suitable for smooth-bore guns and small arms.

In my copending application, Serial Number 618,388, is described a process for modifying the surface of a dense colloided nitrocellulose powder grain so that it will approach the rate of burning of the so-called l0 bulk powders, and in order that this rate of burning may beso accelerated that the initial pressure is developed. at the rate required to enable its utilization in and render it suitable for cylinder guns and small arms.

In accordance with the process described, a dense .colloided nitro-cellulose powder grain, (such as military ammunition salvaged from the war, sub-divided to the required extent) is modified so as to form a .20 dense core surrounded b a less dense and porous envelope. This is accomplished by swelling the surface of the grain to the desired depth of penetration and the swollen envelope so formed is then fixed. This fixing is accomplished in such a manner as to cause not only interruption of the swell ng in order to secpre an envelope of the desired depth, but also" to break up the surface in order to leave an open and porous envelope which is readily ignitible. One of the objects of this invention, therefore, is to further improve the propellant powder and process.

Another object of this invention is to provide a propellant powder in which the dense colloided nitro-cellulose grain is impregnated with an oxidizer. q

Another object of this invention is to improve the sub-division of the powder grain 40 in order to obtain a fiaky'grain having improved characteristics.

Further objects will appear from the detail description in which is given an example illustrating a practical embodiment of this invention. In this illustration we will assume as a base material a dense colloided. nitro-cellulose powder, such as standard untreated military ammunition salvaged from Application filed September %,.l92 3. Serial No. 660,939.

the war, although the process is equal] ap' plicable to freshly prepared nitro-cel ulose fact warped. This reduction can beaccomplished in any suitable manner so as to secure the desired result. A suitable process comprises in reducing the grains in a beater, such as is used for pulping gun cotton. Such a beater has an anvil or stationary cutter with which cooperates a series of knives. on a drum, and these are immersed and operate in an annular tank which can be filled with water, which water is adapted to circulate in and along the tankand past the cooperating faces of the anvil and knives The action is to slice the powder grains so as to form flakes, that 15, grains whose widths and lengths are much greater than Y their thicknesses. 'By the cooperation of the knives on the drum with the anvil or stationary cutter, the flakes while being formed by slicing the grains, are, however, squeezed or compressed so as to reduce the grain thickness. Moreover these flakes will be uneven and in fact warped. The presence of the water not only prevents ignition but also promotes "the formation of flaky grains. The reduction of the powder grains to'flake form may however, be performed in other ways, as by passing the grains between two burrs or discs rotating face to face and provided with radial teeth, which have a slicing as well as a flattening action.-in that they serve to fiatten out the cut or broken grain in the form of flakes. Furthermore the grains may be flattened by passing the same through heavy calender rolls, and'these flakes may then be further reduced by grinding in any suitable manner. In each case', however, the operations are performed in the presence of water. After flaking, the grains may be dried and screened to remove any dust, and the screening may be performed to proper 'sizes for difi'erent calibers or arms. Y a

There is thus produced a powder grain which is in the form of a thin flake. A

I thus cause ruptures in the gun. The flake powder owing to its shape and method of production eliminates these objectionable features and produces a powder which burns in the proper manner to produce the highest ballistic efl'iciency. The,uneven or warped character of the flake alsqhas the advantage over a lain flat grain in that two uneven or warpe grains cannot lie flat against one another; accordingly the burning of each flake can proceed uniformly, thereby avoiding irregular ballistics. I

The powder so reduced may be used to advantage in smooth-bore guns without further treatment. It is, however, preferably given the further treatment described in the application referred to; Furthermore the hereinafter described treatment may be ap'-. plied to a powder not of the flake form. A ractical example of this treatment will now e described;

Takin again,for illustration, as a base a dense co oided nitro-cellulose powder, this is sub-divided or reduced to the required stateof divisions to form grains either of the flaky form or otherwise. This powder is then intimately mixed with 'a solid nitrohydrocarbon, such as dinitro-toluene, in the proportion of ninety-eight (98%l parts of the powder and two 2) parts of t e solvent, although the proportions may be varied within limits tosuit r uirements. The mixture is then introduced into a tank provided with a stirring mechanism, or into a'tumbling barrel, which tank or barrel has been previously filled with water and raised to a temperature of '7 5 to 100 (1., depending upon the nature of the solvent used. The temperature is maintained (by supplying live steam or water to a jacket or by the di-v rect action oi steam) for a suitable-period, in case where dinitro-toluene is used for a period of about hour, while the powder and the solid solvent are rumbled together in the solution. The solvent under the influence of heat melts and distributes itself uniformly over the powder grain, and due to its solvent action penetrates the same, with the result that there is formed an envelope of nitro-cellulose collided' with dinitro-toluone, which is less dense than the body or core of the grain. Cold water is now admitted to the mixture so as to rather suddenly chill the contents of the barrel, therea cracked and porous envelope, and the grain 1 as a whole has become of greater volume.

The treatment as just described is fully described in; application Serial No. 618,388 referred to, to which reference is had for further detail description. In accordance with the present invention, however, the powder grain is impregnated with an oxidizer, such asa suitable metallic nitrate, of

which barium nitrate, potassium nitrate and sodium' nitrate are examples. These salts readily enter the porous envelope when applied in the form of a solution, which solution enters the pores or cracks; upon drying the salt remains behind in the envelope as an integral part of thepowder grain.

As a practical illustration of a practical embodiment of this invention, the nitrate salt is added to the water during the application of the dinitro-toluene, since it will not interfere with the action of the solvent. Accordingly the heating and chilling steps are performed in the presence of this salt solution acting as a heating medium, and this solution enters the pores and cracks of the grain envelope When now the grains so treated are removed from thesolution and dried in the usual manner, the enrvelope'will not contract but will remain porous due to the chilling step while upon evaporation of the water from the salt solution in the pores, this salt will remain behind in the pores. The quantity of oxidizer introduced into the powder grain depends lar ely upon the strength of the solution, an its strength need not be fixed since the solution may be reused again and a ain. However, as a practical example a Eve percent solution will give satisfactory results.

. It will, herefore, be seen that a powder' grain is formed which has a core of dense colloided nitro-cellulose and a porous envelope impregnated with an oxidizer. The

structure of the envelope is, therefore, such that it is not only readily ignitible, but it will continue to burn at a higher rate under a reduced pressure, so' that the burning of the envelope supplies the necessary temperature and pressure to afi'ord complete combustion of the balance'of the grain. This rate of combustion can be regulated by variation of the thickness of the envelope, which can readily be controlled byextending the pene tration period of the. solvent. Moreover the impregnation of the grain with the oxidizer Wlll produce a grain which contains suflicient oxygen for complete combustion; accordingly the weight of the charge is reduced. to obtain e ual ballistics. While the impregnation 0 colloided nitro-cellulose pow ers generally, it is 'ofespecial advantage when applied to the uneven or flaky grains as heretofore described, since this renders the resultant pow- I with the salt may be accomplished after the grain has been acted upon by the solvent and chilled; thus the powder unay, after the action of the solvent thereonand after the same has been fixed by chilling, be taken from the tank or tumbling barrel and dumped into a tank or vat containing ,the

salt solution, and after penetration for a suitable period, the powder may be removed from the solution and dried. It is further obvious that various changes may be made in details without departing from the spirit of this invention; it is, therefore, to be understood that this invention is not to be limited to the specific details shown and described.

Having thus described the invention, what is claimed is:

1. A propellant powder grain of dense colloided nitro-cellulose the surface layer onlyof which is impregnated with an oxidizer.

2. A propellant powder grain of dense colloided nitro-cellulose the surface layer only of which is impregnated with a metallic nitrate.

3. A propellant powder grain of dense colloided nitro-cellulose the surface of which is porous and has an oxidizer within and filling the pores.

4. A propellant powder grain comprising, a dense colloided nitro-cellulose core surrounded by a porous envelope impregnated with an oxidizer.

' 5. A propellant powder grain of dense colloided nitro-cellulose the surface of which is L. partially decolloided and impregnated with an oxidizer.-

v 6. A propellant powder grain of dense colloided nitro-cellulose the surface layer only 'of which is colloided with a solvent and impregnated with an oxidizer.

7. A propellant powder grain of dense colloided nitro-cellulose the surface of which contains a precipitated nitro-hydrocarbon and a metallic nitrate. v

8. In the art .of maln'ng propellant powder, the process comprising, rendering the surface of the grain porous and impregnating the surface with an oxidizer.

9. In the art of making propellant powder,

a grain may be ap lied to dense the process comprising, swelling the surface of the grain and impregnating the surface with an oxidizer.

10. In the art of making propellant powder, the process comprising, swelling the surface of the grain, impregnating the surface .With an oxidizer, and fixing the envelope so formed.

' 11. The process comprising, subjecting 'a dense nitro-qellulose colloid to the action .of a swelling medium and impregnating the envelope so formed with an oxidizer.

12. The process comprising, subjectin a dense nitro-cellulose colloid to the action of a solvent and an oxidizer in order to impregnate the surfacelayer only thereof.

18. The process comprising, subjecting-a 1 dense nitro-cellulose colloidv to the action of a solvent, chilling the envelope so formed, and impregnating the envelope with an ox izer.

14. The process comprising, heating a.

dense nitro-cellulose colloid with a solid nitro-hydrocarbon solvent and impregnating the-envelope so formed with a metallic nitrate. Y

15; The process comprising, heating a dense nitro-cellulose colloid with a solid nitro-hydrocarbon' in a water solution of a metallic nitrate.

16. The process comprising, heating a dense nitro-cellulose colloid with a solid nitro-hydrocarbon in a water solution of a metallic nitrate and chilling the same in such solution.

17. The process comprising, reducing dense colloided nitro-cellulose powder grains in the presence of water so as to form flakes. 18. The process com rising, grinding dense colloided nitro-cellu ose powder grains in the presence of water into flakes.

. 19. 'The process comprising, reducing dense colloided nitro-cellulose'powder grains and forming the same into flakes.

- 20. The process comprising, breaking dense colloided nitro-cellulose powder grains and flattening the same to form flakes.

21. .The process comprising, slicing dense colloided nitro-cellulose powder grains so as to'form flakes.

22. The process comprising, slicing dense colloided nitro-cellulose powder grains and reducing the thickness of the same.

23. A broken propellant powder grain of dense colloided nitro-cellulose in the form of a flake.

24. A propellant powder grain of dense colloided nitrocellulose in the form of an irregular flake.

25. A propellant powder grain of dense colloided nitro-cellulose in the form of a warped flake.

26. A propellant powder .grain of dense colloided nitro-cellulose in the .form of a flake the surface of which is porous.

27. A propellant owder ain of dense 29. A propellant owder grain of dense colloided nitro-cellu ose in 't e form of a colloided nitro-cellu ose in the form of a .fiake the surface of which is impregnated flake the surfaceof which is partially dewith an oxi dizer. V colloided and impregnated with an oxidizer. 28. A propellant powder grain of dense In testimony whereof I aflix my signacolloided nitro-cellulose in the form of a ture this 22nd day of August, 1923. flake the surface of which'is partially deu colloided. A ARTHUR S. ONEIL. 

